For many years floating docks have been constructed utilizing sealed containers of air such as barrels and more recently blocks of foam such as styrofoam. Because of damage to and from wildlife, foam floats now generally consist of blocks of closed cell foam encapsulated within a plastic skin or covering to provide the desired flotation. Such air or foam blocks have been economical and easy to use as modular blocks in dock building but have generally resulted in relatively unstable platforms particularly when several people attempt to stand along one edge of an elongated dock. The tipping or tilting of the dock, especially narrower ones has been a persistent problem.
One attempt to solve this problem in a floating dock is shown in U.S. Pat. No. 5,347,948 to Rytand. Rytand shows spaced apart longitudinal beams or stringers forming elongated chambers in which he places foam blocks so as to fill the upper two thirds of the chamber. The lower one third of the chambers are allow to fill with water by seepage when the dock is installed. The water tends to act as ballast. The longitudinal beams tend to limit longitudinal deflection and the ballast tends to limit lateral tipping. This construction however is cumbersome to make and handle, especially out of the water, and is limited in the sizes and shapes that can be easily and economically made.
Another attempt to stabilize a floating dock structure is shown in NY State Department of Environmental Conservation Dwg "Town of Bethlehem" dated November 1996. Here a flat butterfly plate has been mounted across the width of a dock with a number of holes formed therein. The performance of this butterfly plate is unknown but it would appear to offer some improvement in stability of the dock structure.